460 BELL SYSTEM TECHNICAL JOURNAL 



ConsequentK-, an extended program of measurements was initiated 

 to disclose the transmission conditions obtaining throughout the 

 twenty-four hours of the day and the various seasons of the year. 

 The methods used in conducting these measurements and the results 

 obtained during the first few months of them have already been 

 described in the paper previously mentioned. The results there 

 reported upon were limited to one-way transmission from the I'nited 

 Stales t(i luigland upon the telcplioiie channel. .Since then the 



Fig. 1 



measurements have been extended to include transmission on several 

 frequencies in each direction from radio telegraph stations in addition 

 to the 57 kilocycles employed by the telephone chaiiiiel. 



Tlie present paper is, therefore, in tlic iiaiiirc of a rtporl upon the 

 results thus far obtained in work currenll\- uiiilcr w.»\-. It seems 

 desirable to make public these results because of tin- large amount 

 of \aluable data which they have already yielded, and because of the 

 timely interest which attaches to information bearing u|>on the 

 fimdamentals of radio transmission. The carr>-ing on of this ex- 

 tensive measurement program has been made possible through the 

 co()i)eration of engineers of the following organizations: in the I'nited 

 Slates— The American Telephone and Telegraph Company and the 

 Bell Teleiihonc Laboratories, Inc., with the Radio Corporation of 

 America and its Associated Companies; in England — The Inter- 

 national Western Electric Compaiu', Inc., and the British Post Office. 



